Yes, the x86_64 code in Mesa is currently AMD only, as it uses 3dnow. Some
functions probably could be fixed easily (those only using prefetch, prefetchw
and femms by exchanging these instructions with the equivalent sse
instructions), however some actually use the instructions of 3dnow operating on
vec2 data, (pfmul, pfadd etc.), they look difficult to optimize with sse (they
aren't optimized in the x86 sse path neither).
As a workaround, use a build without assembly optimization (linux-dri instead of
linux-dri-x86-64).